Tip shield for needle stick prevention

BACKGROUND OF THE INVENTION

This disclosure relates generally to vascular access systems and methods, including hypodermic needles, needle assemblies, catheter assemblies, and devices used with catheter assemblies. Generally, vascular access systems are used for communicating fluid with the vascular system of patients and may include one or more vascular access devices. For example, catheters are used for infusing fluid, such as saline solution, various medicaments, and/or total parenteral nutrition, into a patient, withdrawing blood from a patient, and/or monitoring various parameters of the patient's vascular system.

Intravenous (IV) catheter assemblies are among the various types of vascular access systems, and over-the-needle peripheral IV catheters are a common IV catheter configuration. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. The introducer needle is generally a hypodermic needle forming a part of a needle assembly to help guide the needle and to facilitate its cooperation with the catheter. At least the inner surface of the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitates insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin. The catheter and introducer needle are generally inserted at a shallow angle through the patient's skin into a blood vessel.

In order to verify proper placement of the needle and/or catheter in the blood vessel, the clinician generally confirms that there is “flashback” of blood in a flashback chamber, which is generally associated with a needle assembly. Once proper placement of the distal tip of the catheter into the blood vessel is confirmed, the clinician may apply pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal of the introducer needle and the catheter. This finger pressure occludes the vessel, minimizing further blood flow through the introducer needle and the catheter.

The clinician may then withdraw the introducer needle from the catheter. The introducer needle may be withdrawn into a needle tip shield or needle shield that covers the needle tip and prevents accidental needle sticks. In general, a needle tip shield includes a housing, a sleeve, or other similar device that is designed such that when the needle is withdrawn from the patient, the needle tip will be trapped/captured within the needle tip shield. The purpose of the needle tip shield is to house the tip of the needle in a secure location, thereby reducing the possibility of needle sticks when the needle and needle tip shield are separated properly from the catheter, which is left in place to provide intravenous access to the patient.

The separation of the needle assembly from the catheter portions of the catheter assembly presents numerous potential hazards to the clinicians and others in the area. As indicated above, there is a risk of accidental needle sticks if the needle tip is not secured properly in a needle tip shield. Additionally, because the needle has been in contact with blood in the patient's vasculature, blood is often present on the exterior of the needle and is often present inside the lumen of the needle. As the needle is withdrawn, there is a risk that this blood will drip from the needle tip or come into contact with other surfaces to expose clinicians and equipment to blood. The present disclosure presents systems and methods to significantly limit and/or prevent needle sticks, and in some implementations, blood exposure.

SUMMARY OF THE INVENTION

The systems and methods of the present disclosure have been developed in response to problems and needs in the art that have not yet been finally resolved by currently available vascular access systems and methods. Thus, these systems and methods are developed to provide safer vascular access systems, methods of manufacturing the same, and methods of using the same to reduce needle sticks.

A vascular access system within the scope of the present invention includes a hypodermic needle, a tip shield, and a housing. The needle includes a needle shaft that terminates at a needle tip. The tip shield includes an enclosure defining a chamber. The enclosure includes at least one side wall configured to slidably engage the needle shaft, a closed distal end, and a proximal end slidably engaging the needle shaft. Accordingly, the tip shield may be disposed at an angle with respect to the needle when the needle extends through both the side wall and the proximal end of the tip shield. The housing of the vascular access system defines a passageway with respective proximal and distal openings through which the needle slidably extends. The proximal opening of the housing releasably retains the tip shield in the passageway. Through a variety of possible implementations, at least one of the needle and the tip shield are adapted to prevent the needle shaft from being completely withdrawn from the tip shield. Additionally, the tip shield is adapted to secure the needle tip in the chamber upon withdrawal of the needle tip into the chamber.

In some implementations, vascular access systems within the scope of the present invention include a needle having an enlarged shaft region proximate to the needle tip. The enlarged shaft region cooperates with and engages an opening in the proximal end of the tip shield adapted to slidably engage the needle shaft without allowing the enlarged region to pass proximally through the opening. Additionally or alternatively, some implementations may include a tip shield having an elongate hollow body defining the chamber and a needle shaft port, which may be in a side wall of the elongate body. In such implementations, the needle shaft extends through the opening in the proximal end of the tip shield and the needle shaft port when the needle is disposed in the housing, which disposes the tip shield at an angle with the needle shaft. The opening in the proximal end of the tip shield may be configured as a pivot hole that engages the enlarged shaft region during proximal movement of the needle relative to the housing and further proximal movement of the needle relative to the housing causes the tip shield to pivot at the pivot hole drawing the needle tip into and through the needle shaft port and into the chamber.

These and other features and advantages of the present disclosure may be incorporated into certain embodiments and will become more fully apparent from the following description and appended claims, or may be learned by the practice of the methods and use of the systems as set forth hereinafter. The present disclosure does not require that all the advantageous features and all the advantages described herein be incorporated into every embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only typical embodiments and are not therefore to be considered to limit the scope of the present invention.

<figref idrefs="DRAWINGS">FIG. 1</figref> is an exploded perspective view of an exemplary extravascular system incorporating multiple exemplary vascular access devices.

<figref idrefs="DRAWINGS">FIG. 2</figref> is a cross-sectional view of a portion of an exemplary extravascular system.

<figref idrefs="DRAWINGS">FIG. 3</figref> is a cross-sectional view of a portion of a vascular access system showing an exemplary relationship between a housing, a tip shield, and a needle.

<figref idrefs="DRAWINGS">FIG. 4</figref> is a cross-sectional view of the system of <figref idrefs="DRAWINGS">FIG. 3</figref> shown with the needle further withdrawn from the housing.

<figref idrefs="DRAWINGS">FIG. 5</figref> is a cross-sectional view of the system of <figref idrefs="DRAWINGS">FIG. 3</figref> shown with the needle completely withdrawn from the housing and the tip shield enclosing the needle tip.

<figref idrefs="DRAWINGS">FIG. 6</figref> is a schematic cross-sectional of a portion of an exemplary extravascular system.

<figref idrefs="DRAWINGS">FIG. 7</figref> is a top plan view of a tip shield shown in an unformed stage.

<figref idrefs="DRAWINGS">FIG. 8</figref> is a perspective view of the tip shield of <figref idrefs="DRAWINGS">FIG. 7</figref> shown in a partially-formed stage.

<figref idrefs="DRAWINGS">FIG. 9</figref> a perspective view of the tip shield of <figref idrefs="DRAWINGS">FIG. 7</figref> shown in a formed stage.

<figref idrefs="DRAWINGS">FIG. 10</figref> is an exploded perspective view of an alternative tip shield molded from a plastic material.

<figref idrefs="DRAWINGS">FIG. 11</figref> is a top plan view of a tip shield shown in an unformed stage.

<figref idrefs="DRAWINGS">FIG. 12</figref> is a perspective view of the tip shield of <figref idrefs="DRAWINGS">FIG. 11</figref> shown in a formed stage.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a cross-sectional view of another embodiment of the tip shield of the present invention.

DETAILED DESCRIPTION

The presently preferred embodiments of the present disclosure will be best understood by reference to the drawings. It will be readily understood that the components of the present disclosure, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description, as represented in the figures, is not intended to limit the scope of the claims, but is merely representative of presently preferred embodiments.

Referring to <figref idrefs="DRAWINGS">FIG. 1</figref>, the perspective view illustrates an example of an extravascular system <b>10</b>, or vascular access system, including multiple vascular access devices <b>12</b>. In this example, the extravascular system <b>10</b> includes a catheter assembly <b>14</b> and a needle assembly <b>16</b>. The catheter assembly <b>14</b> has a proximal end <b>20</b> and a distal end <b>22</b> and includes a catheter <b>24</b> having an opening <b>28</b> at the distal end <b>22</b> of the catheter assembly <b>14</b> and a catheter hub <b>26</b> disposed at the proximal end <b>20</b> of the catheter assembly <b>14</b>. The catheter assembly <b>14</b> also defines a lumen <b>30</b> extending from the proximal end <b>20</b> to the distal end <b>22</b>.

Proximal end <b>20</b> of catheter assembly <b>14</b> may be configured in any suitable manner to facilitate its cooperation with other vascular access devices. Two exemplary configurations are illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>. Shown in solid lines in <figref idrefs="DRAWINGS">FIG. 1</figref>, the catheter assembly proximal end <b>20</b> may be configured with positioning ridges and grooves <b>32</b> adapted to coordinate with similar features on adjoining devices. The positioning ridges and grooves <b>32</b> are examples of coupling systems that may be used to position and/or retain another vascular access device, such as adapters, flow control plugs, dead-ender caps, or other devices (not shown), attached to the catheter hub <b>26</b> in a desired orientation. Other suitable coupling and positioning systems may be used. For example, traditional Luer lock features may be included, which may be male or female Luer lock configurations. <figref idrefs="DRAWINGS">FIG. 1</figref> further illustrates, in dotted lines, that the catheter assembly <b>14</b> may optionally be configured with an activating housing <b>34</b> adapted to cooperate with particular aspects of the present vascular access systems. The activating housing <b>34</b> will be described in greater detail below, including at least with reference to <figref idrefs="DRAWINGS">FIG. 3</figref>. The activating housing <b>34</b> is one example of a housing <b>36</b> within the scope of the present disclosure.

Continuing with <figref idrefs="DRAWINGS">FIG. 1</figref>, the vascular access system <b>10</b> includes a needle assembly <b>16</b> includes a hypodermic needle <b>40</b> having a needle shaft <b>42</b> adapted to extend through the lumen <b>30</b> of the catheter assembly <b>14</b>. The needle tip <b>44</b> and other aspects of the needle <b>40</b> are obscured in <figref idrefs="DRAWINGS">FIG. 1</figref> by the position of the tip shield <b>60</b> and will be illustrated and described in connection with subsequent figures. The illustrated needle assembly <b>16</b> includes a needle hub <b>46</b>, which may be provided in some implementations to facilitate the insertion, removal, and control of the needle <b>40</b> and the needle assembly <b>16</b> generally. The proximal end of the needle assembly <b>16</b> may be adapted to cooperate with yet additional vascular access devices <b>12</b>, such as a flow control plug <b>48</b> as illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>.

While the needle assembly <b>16</b> illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref> is configured for use with the catheter assembly <b>14</b>, other needle assemblies and vascular access systems within the scope of the present invention may include hypodermic needles (not shown) adapted for other applications. For example, the needle assembly <b>16</b> may or may not include the needle hub <b>46</b> of the configuration illustrated. Additionally or alternatively, the vascular access systems of the present disclosure and invention may be adapted for use in injections rather than in cooperation with catheters.

<figref idrefs="DRAWINGS">FIG. 1</figref> further illustrates that the extravascular system <b>10</b> may include an optional adapter housing <b>50</b>. The adapter housing <b>50</b>, when included, may be configured to cooperate with the tip shield <b>60</b>, such as to accommodate the tip shield <b>60</b> during use of the extravascular system <b>10</b> and to activate the tip shield <b>60</b> when the needle <b>40</b> is being withdrawn from the catheter assembly <b>14</b>. The adapter housing <b>50</b> is illustrated schematically in <figref idrefs="DRAWINGS">FIG. 1</figref> representative of the variety of configurations the adapter housing may take in cooperating with aspects of the needle assembly <b>16</b> and the catheter housing <b>14</b>. For example, the distal end <b>52</b> of the adapter housing <b>50</b> may be configured with Luer lock features (not shown) to cooperate with mating Luer lock features on the catheter hub <b>26</b>. Similarly, the proximal end <b>54</b> of the adapter housing <b>50</b> may be adapted to coordinate with the needle hub <b>46</b> or other aspect of the needle assembly <b>16</b>. The adapter housing <b>50</b> is yet another example of a suitable housing <b>36</b> within the scope of the present disclosure.

With continuing reference to <figref idrefs="DRAWINGS">FIG. 1</figref>, the needle tip <b>44</b> is illustrated as being housed within the tip shield <b>60</b>. The tip shield <b>60</b> shown in <figref idrefs="DRAWINGS">FIG. 1</figref> is representative of needle shield <b>60</b> within the scope of the present disclosure. As used herein, the term tip shield <b>60</b> shield refers to a structure that is adapted to be positioned adjacent to the needle tip <b>44</b> when the needle tip has been withdrawn, such as withdrawn from the catheter assembly <b>14</b> or a patient's vascular system, to encapsulate the needle tip <b>42</b>.

<figref idrefs="DRAWINGS">FIG. 2</figref> provides an illustrative cross-sectional view of a portion of the extravascular system <b>10</b>, including the catheter assembly <b>14</b>, the adapter housing <b>50</b>, and the needle assembly <b>16</b>. As seen in <figref idrefs="DRAWINGS">FIG. 2</figref>, the catheter assembly <b>14</b> and the adapter housing <b>50</b> are adapted to associate proximal end <b>20</b> to distal end <b>52</b>. Additionally, the proximal end of the adapter housing <b>50</b> associates with the distal end of the needle hub <b>46</b>. The adapter housing <b>50</b> defines a passageway <b>54</b> having a proximal opening <b>56</b> and a distal opening <b>58</b>. As shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, the adapter housing <b>50</b> accommodates the tip shield <b>60</b> within the passageway <b>54</b>.

Moreover, the proximal opening <b>56</b> of the housing <b>50</b> is configured to releasably retain the tip shield <b>60</b> within the housing. The retention of the tip shield <b>60</b> may be accomplished by disposing the side walls of the proximal opening <b>56</b> close enough together to create a frictional fit between the tip shield <b>60</b> and the proximal opening of the housing, as illustrated. Other suitable configurations may be utilized to releasably retain the tip shield <b>60</b> in the housing <b>50</b>, such as disposing a yielding finger or other extension member into the path of the proximal opening <b>56</b> that allows the tip shield <b>60</b> to pass only under a certain minimum force. The releasable retention of the tip shield <b>60</b> may be implemented to limit or prevent the inadvertent separation of the needle assembly from the catheter assembly <b>14</b>. Additionally or alternatively, the releasable retention of the tip shield <b>60</b> may be configured to assist in the activation or transition of the tip shield from a use position (as seen in <figref idrefs="DRAWINGS">FIG. 2</figref>) to a protection position (as seen in <figref idrefs="DRAWINGS">FIG. 1</figref>).

<figref idrefs="DRAWINGS">FIG. 2</figref> further illustrates that extravascular system <b>10</b> may include one or more blood stabilizing materials <b>38</b> to further limit the risk of blood exposure. As seen in <figref idrefs="DRAWINGS">FIG. 2</figref>, the blood stabilizing material <b>38</b> is disposed inside the passageway <b>54</b> of the housing <b>50</b>. Additionally or alternatively, blood stabilizing materials may be disposed inside or outside the adapter housing <b>50</b>, inside and/or outside the tip shield <b>60</b>, or in any other suitable location to control the spillage or flow of blood. The blood stabilizing material <b>38</b> is shown schematically to represent the variety of manners in which such material may be incorporated into the present vascular access systems and devices. The blood stabilizing material <b>38</b> may be a coagulant, an absorbent, or another material for stabilizing the blood to reduce the exposure risk. Similarly, the blood stabilizing material <b>38</b> may be a liquid, a solid, a gel, a powder, granular, or any other consistency appropriate for its use. The blood stabilizing material <b>38</b> may be disposed in a porous membrane or container (not shown) that allows the blood to enter while preventing the exit of the blood stabilizing material <b>38</b>.

Once the blood has been stabilized by absorption and/or coagulation by contact with the blood stabilizing material <b>38</b>, the risk of blood being splattered is significantly reduced and the exposure risk is still further minimized due to the stability of the blood (i.e., being coagulated or absorbed, the blood does not contaminate other objects or persons). The clinician is then left with a single, defined source of blood exposure risk at a distal exterior surface of the needle tip shield <b>60</b>. The implementation of blood stabilizing material <b>38</b> together with the housing <b>36</b> configured to allow the tip shield to close before the needle <b>40</b> is completely withdrawn may further reduce the risk of blood exposure.

As suggested, the housing <b>36</b>, whether implemented as part of a catheter assembly, as a separate adapter, or as part of a needle assembly, may be adapted to allow the tip shield <b>60</b> to close or otherwise entrap the needle tip <b>44</b> before the needle is fully withdrawn. <figref idrefs="DRAWINGS">FIG. 2</figref> provides an exemplary illustration of a tip shield <b>60</b> including needle trap means configured to allow the needle shaft <b>42</b> to slide within the trap means while securing the needle tip <b>44</b> once it is withdrawn into the tip shield. For example, and as illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, the tip shield <b>60</b> may include an enclosure <b>62</b> including at least one side wall <b>64</b>, a closed distal end <b>66</b>, and a proximal end <b>68</b>. The proximal end may be adapted to slidingly engage the needle shaft <b>42</b>, such as through an opening (not shown in <figref idrefs="DRAWINGS">FIG. 2</figref>). Similarly, at least a portion <b>64</b> of the side wall of the enclosure <b>62</b> may be adapted to slidingly engage the needle shaft <b>42</b>. For example, a side wall may be provided with a needle shaft port <b>72</b> adapted to slidingly engage the needle shaft <b>42</b>.

To prevent the needle <b>40</b> from being withdrawn proximally from the tip shield <b>60</b>, thereby exposing the needle tip <b>44</b>, at least one of the needle <b>40</b> and the tip shield <b>60</b> may be configured to retain the needle. For example, the needle shaft <b>42</b> may be provided with an enlarged shaft region <b>74</b> (seen in <figref idrefs="DRAWINGS">FIG. 3</figref>) proximate the needle tip <b>44</b> or the needle tip itself and the opening in the proximal end <b>68</b> of the enclosure <b>62</b> may be configured to prevent the complete withdrawal of the needle tip <b>44</b> from the tip shield <b>60</b> in the proximal direction. Additionally, the closed distal end <b>66</b> of the tip shield <b>60</b> prevents distal exit of the needle tip <b>44</b> from the tip shield <b>60</b> once the needle tip is disposed within the chamber <b>76</b> defined by the enclosure <b>62</b>.

As will be described in further detail in connection with <figref idrefs="DRAWINGS">FIGS. 7-12</figref>, the tip shield <b>60</b> is configured to allow the needle shaft to extend through a sidewall <b>64</b> of the enclosure <b>62</b>. Accordingly, with the needle shaft extending through the proximal end of the enclosure and the sidewall of the enclosure, the needle shaft is disposed at an angle with respect to the needle shaft. Depending on the configuration of the needle shaft port <b>72</b>, the angle between the needle shaft and the tip shield may vary. One exemplary relationship is shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

Referring now to <figref idrefs="DRAWINGS">FIGS. 3-5</figref> and <b>13</b> collectively, a cross-sectional view of a needle assembly <b>16</b> and a housing <b>36</b> are illustrated having the needle tip <b>44</b> and the tip shield <b>60</b> in various states of relationship with the housing <b>36</b>. As illustrated, the housing <b>36</b> is representative of both an activating housing <b>34</b> as may be part of a catheter assembly <b>14</b> and an adapter housing <b>50</b>, as well as other housing configurations that may be implemented. One exemplary manner through which the present tip shields <b>60</b> and vascular access systems <b>10</b> reduce and/or prevent needle sticks is illustrated in <figref idrefs="DRAWINGS">FIGS. 3-5</figref>. Other suitable methods and configurations may similarly be used implementing the principles of the present disclosure. As just one example, the tip shield <b>60</b> may be retained on the needle shaft <b>42</b> through use of a tether (not shown) coupled to the tip shield and the needle hub <b>46</b> where the tether is dimensioned to be shorter than the needle shaft.

<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates an exemplary relationship between the housing <b>36</b>, the tip shield <b>60</b>, and the needle <b>40</b> when the needle is being withdrawn but before the enlarged shaft region <b>74</b> has entered the tip shield. As discussed above, the needle tip <b>44</b> is being withdrawn proximally and is positioned adjacent the distal opening <b>58</b> of the housing <b>36</b>. The needle shaft <b>42</b> extends through the proximal opening <b>56</b> of the housing <b>36</b>, the proximal end <b>68</b> of the tip shield <b>60</b>, and the sidewall <b>64</b> of the tip shield.

Referring now to <figref idrefs="DRAWINGS">FIG. 4</figref>, the needle <b>40</b> is shown being further withdrawn in the proximal direction. The enlarged shaft region <b>74</b>, here illustrated as a ferrule, near the needle tip <b>42</b> has passed through the sidewall <b>64</b> of the tip shield and is shown engaged with the proximal end <b>68</b> of the tip shield. It is noted that the enlarged shaft region <b>74</b> may be provided by a ferrule or by other means. As the enlarged shaft region <b>74</b> engages the proximal end of the tip shield, the needle shaft is no longer able to slide through the tip shield and the tip shield position changes from the disposition shown in <figref idrefs="DRAWINGS">FIG. 3</figref>. As the needle is continually moved proximally relative to the housing, the needle shaft <b>42</b> and the tip shield <b>60</b> will try to move together. However, the proximal opening <b>56</b> of the housing <b>36</b> does not allow such movement without first moving the tip shield <b>60</b> relative to the needle shaft <b>42</b>. As illustrated, the tip shield <b>60</b> rotates becoming more coaxial with the needle shaft. As the needle <b>40</b> and the tip shield <b>60</b> are drawn through the proximal opening <b>56</b> of the housing <b>36</b>, the needle tip <b>44</b> is pressed further into the chamber <b>76</b> of the tip shield <b>60</b>. The length of the tip shield <b>60</b> and the distance from the enlarged shaft region <b>74</b> to the needle tip <b>44</b> may be coordinated to allow the needle tip to be seated in or received by the tip shield. Any suitable length may be used while shorter lengths may be preferred for the convenience of the users and the costs of materials.

It should be noted by comparing the illustrations in <figref idrefs="DRAWINGS">FIGS. 3 and 4</figref> that the needle shaft port <b>72</b> and the opening in the proximal end <b>68</b> may be configured to allow some movement of the needle shaft to accommodate the rotation of the tip shield relative to the needle shaft. For example, the opening in the proximal end of the tip shield may be configured as a slot having sufficiently narrow width to retain the needle tip in the chamber <b>76</b> and a length sufficient to accommodate the rotation of the tip shield. Similarly, the needle shaft port <b>72</b> or other opening in the sidewall <b>64</b> of the tip shield may be sized to allow such movement.

As the needle <b>40</b> and the tip shield <b>60</b> are further drawn through the proximal opening <b>56</b> of housing <b>36</b>, the tip shield <b>60</b> continues to move relative to the needle shaft to a final position in which the needle tip <b>44</b> is pressed completely through the needle shaft port <b>72</b> into the chamber <b>76</b> of the tip shield to encapsulate the needle tip <b>44</b>, which is best seen in <figref idrefs="DRAWINGS">FIG. 5</figref>. As illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref>, the tip shield <b>60</b> is longer than the length of the needle <b>42</b> from the needle tip <b>44</b> to the enlarged shaft region <b>74</b>. Thus, the needle tip <b>44</b> is fully encased within the tip shield <b>60</b>.

The enlarged shaft region <b>74</b> together with the proximal end of the tip shield prevent the needle tip <b>44</b> from exiting the tip shield proximally while the closed distal end <b>66</b> of the tip shield prevents the need tip from exiting distally. As will be seen in the discussion of <figref idrefs="DRAWINGS">FIGS. 7-12</figref>, the opening in the sidewall <b>64</b> is configured to prevent exit of the needle shaft <b>42</b> and/or needle tip <b>44</b> once the needle tip is drawn into the chamber <b>76</b>.

The releasable retention of the tip shield <b>60</b> by the housing <b>36</b> may be configured to ensure that the needle tip <b>44</b> is completely received into the chamber <b>76</b> before the needle is separated from the housing. Such a configuration ensures that the needle tip <b>44</b> is not exposed and thereby prevents needle sticks. Additionally, enclosing the needle tip <b>44</b> in the tip shield <b>60</b> before the needle tip <b>44</b> exits the housing may reduce the risk of blood exposure as well.

<figref idrefs="DRAWINGS">FIG. 13</figref> illustrates essentially the same device as illustrated in <figref idrefs="DRAWINGS">FIGS. 3-5</figref>, however, the device is provided with a leaf spring <b>150</b>. Leaf spring <b>150</b> biases the tip shield <b>60</b> upwardly as the needle is withdrawn. The leaf spring <b>150</b> simply provides additional force in an upward direction to assure that the needle is ultimately encased within the tip shield <b>60</b>.

<figref idrefs="DRAWINGS">FIG. 6</figref> presents a cross-sectional view similar to the view of <figref idrefs="DRAWINGS">FIG. 3</figref>. <figref idrefs="DRAWINGS">FIG. 6</figref> schematically illustrates a housing <b>36</b> configured as an activating housing <b>34</b> that is formed as part of the catheter assembly <b>14</b>, or more particularly as part of the catheter hub <b>26</b>. The elements and the relative positions of the elements are the same in <figref idrefs="DRAWINGS">FIG. 6</figref> as they are in <figref idrefs="DRAWINGS">FIG. 3</figref> and little more description is necessary. It should be noted that the proximal opening <b>56</b> of the activating housing <b>34</b> may be configured to releasably retain the tip shield and to cause the tip shield to move into a protecting position that is at least substantially coaxial with the needle shaft. <figref idrefs="DRAWINGS">FIG. 6</figref> is merely a schematic representation of a catheter hub <b>26</b> adapted to cooperate with tip shields of the present disclosure. Other suitable and more developed configurations may be used as well.

Turning now to <figref idrefs="DRAWINGS">FIGS. 7-12</figref>, additional details of the tip shield are provided along with various examples of methods of constructing the tip shield. For example, <figref idrefs="DRAWINGS">FIGS. 7-9</figref> provide top plan and perspective views of the tip shield <b>60</b> at various stages of the manufacturing process. The tip shield may be made of any suitable material that is resistant to penetration by a needle tip. In the illustrated configuration of <figref idrefs="DRAWINGS">FIGS. 7-9</figref>, the tip shield <b>60</b> is made from a stamped sheet <b>80</b> (<figref idrefs="DRAWINGS">FIG. 7</figref>) of stainless steel or other suitable, non-corroding metal or plated metal. The sheet <b>80</b> includes a rectangular body <b>82</b>, a dependent proximal disk <b>84</b> with a slot <b>86</b> or other opening of a length sufficient to allow the tip shield <b>60</b> to pivot relative to the needle shaft <b>42</b>, as discussed above, and a width to closely slidably receive the shaft <b>42</b> of needle <b>40</b> but to not pass the enlarged shaft region <b>74</b>. The sheet <b>80</b> further includes a dependent distal disk <b>88</b>, a pair of proximal tabs <b>90</b>, and a pair of distal tabs <b>92</b>. The tabs <b>90</b>, <b>92</b> are optional, but may be used to facilitate the formation of the tip shield <b>60</b>, as seen in <figref idrefs="DRAWINGS">FIG. 9</figref>. Alternatively, the proximal and distal disks may be coupled and joined to the body through other means.

The body <b>82</b> of sheet <b>80</b> is rolled to form a substantially cylindrical shape, as seen in <figref idrefs="DRAWINGS">FIG. 8</figref>. The opposing longitudinal edges <b>94</b> and <b>96</b> (shown in <figref idrefs="DRAWINGS">FIG. 7</figref>) are brought together and rolled inward into the cylinder forming what may be referred to as having a rounded heart-shaped cross-section. The inwardly rolled opposing longitudinal edges are one manner of forming an opening in the sidewall <b>64</b> through which the needle shaft <b>42</b> may extend. The opposing longitudinal edges may form one example of a needle shaft port <b>72</b>. The longitudinal edges <b>94</b>, <b>96</b> may be disposed to be touching or at a spacing that is smaller than the diameter of the needle shaft <b>42</b>. Accordingly, the needle <b>40</b> cannot pass through the needle shaft port <b>72</b> without deforming the body <b>82</b> of the tip shield <b>60</b>. The material and thickness thereof from which the sheet <b>80</b> is made, material properties, bending/forming geometry, the spacing of the edges <b>94</b>, <b>96</b>, heat treatment or temper of the material, and contour (sharp, tapered, or rounded) of the edges <b>94</b>, <b>96</b> can be varied as desired to control resistance due to drag as the needle <b>40</b> is drawn through the needle shaft port <b>72</b>.

While opposing longitudinal edges <b>94</b>, <b>96</b> may be used to form the needle shaft port <b>72</b>, other suitable configurations may be used. For example, the needle shaft port <b>72</b> may include deforming or biased materials, such as plastics, that allow the needle shaft to move in one direction (e.g. to allow the needle tip to be drawn in to the chamber) but not in the other direction (e.g. to allow the needle tip to be moved out of the chamber).

The proximal end <b>68</b> and distal end <b>66</b> of the tip shield are closed by the respective proximal and distal disks <b>84</b> and <b>88</b>, which may be as seen in <figref idrefs="DRAWINGS">FIG. 9</figref>. This may be accomplished by bending the proximal and distal disks <b>84</b>, <b>88</b> ninety degrees and securing using the proximal and distal tabs <b>90</b>, <b>92</b>. Additionally or alternatively, the disks <b>84</b>, <b>88</b> may be secured to the body <b>82</b> through other means. As illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref>, the tip shield <b>60</b> defines a tip-receiving chamber <b>76</b> of a length slightly larger than the distance from the enlarged shaft region <b>74</b> to the needle tip <b>44</b> to receive the needle tip <b>44</b> and enlarged shaft region <b>74</b> therein.

While the opening in the proximal end <b>68</b> of the tip shield <b>60</b> is illustrated as a relatively narrow slot <b>86</b>, the opening may be configured in any suitable manner. For example, to facilitate assembly of the needle assembly, the opening in the proximal end <b>68</b> and/or the enlarged shaft region <b>74</b> may be configured to facilitate the passage of the enlarged shaft region distally and to retain or prevent the enlarged shaft region during proximal movement. Additionally or alternatively, the construction or assembly of the needle assembly <b>16</b> may be facilitated through strategic order of operations, such as inserting the needle in the reverse direction so that the enlarged shaft region does not have to pass through the tip shield in a distal direction. Other suitable methods for assembling the components of the present disclosure are available.

Referring to <figref idrefs="DRAWINGS">FIG. 10</figref>, an exploded perspective view of an alternative tip shield <b>60</b> that includes a body <b>102</b>, a proximal end cap <b>104</b>, and a distal end cap <b>106</b> each molded from a suitable medical grade plastic material. The body <b>102</b> is extruded or otherwise formed to provide a hollow cylinder <b>108</b> of the substantially cylindrical construction illustrated. The substantially cylindrical cross-section includes an opening in the sidewall thereof, which may be provided by a pair of opposing longitudinal edges <b>110</b>. Additionally or alternatively, the plastic tip shield may be molded to provide a more customized needle shaft port <b>73</b>. Due to the flexibility and customizability of plastics, a variety of options may be available for use of plastic as tip shields. For example, the plastic materials may be adapted to provide a better seal against re-emergence of the needle tip and/or to facilitate the operation of the present extravascular systems <b>10</b>.

The proximal end <b>68</b> and the distal end <b>66</b> of the tip shield may be capped by adhesively or ultrasonically affixing the proximal and distal end caps <b>104</b> and <b>106</b> thereto. In addition, the body <b>102</b> may be constructed of two halves which are joined together by sonic welding, adhesives, snap fitting, or any other attachment mechanism. The plastic material and thickness(es) of the material from which the body <b>102</b> is made, material properties, bending/forming geometry, the spacing between edges, any filler materials added to the plastic material, and the contour (sharp, tapered, or rounded) of the edges can be varied as desired to control resistance due to drag as the needle <b>40</b> is drawn through the valve needle shaft port <b>73</b>.

<figref idrefs="DRAWINGS">FIGS. 11 and 12</figref> provide a schematic illustration of yet another variation on the inventive concepts described herein. <figref idrefs="DRAWINGS">FIG. 11</figref> is comparable to <figref idrefs="DRAWINGS">FIG. 7</figref> illustrating that the tip shield <b>60</b> may be formed from a sheet <b>80</b> of metal or other suitable material. However, it should be noted that the body <b>82</b> of the tip shield <b>60</b> shown in <figref idrefs="DRAWINGS">FIG. 11</figref> includes shaped regions <b>112</b> adjacent the proximal end cap <b>104</b>. Referring to <figref idrefs="DRAWINGS">FIG. 12</figref>, which illustrates the tip shield <b>60</b> formed from the sheet <b>80</b> of <figref idrefs="DRAWINGS">FIG. 11</figref>, it can be seen that the shaped regions <b>112</b> cooperate to form an enlarged opening <b>114</b> in the needle shaft port <b>72</b>. The enlarged opening <b>114</b> may be sized to reduce the frictional resistance against movement of the needle shaft in the needle shaft port <b>72</b>. Accordingly, the shaped regions <b>112</b> may be configured in any suitable manner to create an enlarged opening <b>114</b> suitable for the needle assembly being used (e.g., the enlarged opening <b>114</b> may be larger for larger diameter needle shafts).

Various modifications to the needle tip shields of the present invention are possible while staying within the same inventive concept. For example, the tip shields can be used to protect the tip of any type of sharp, including a cannula in an IV catheter, the tip of a stylet in a long anesthesia needle, a hypodermic needle, surgical blade and other such medical devices. Additionally, the cross-section of the tip shield can be of other shapes such as square, rectangular, triangular, oval, polygonal, and the like.

Still additionally or alternatively, the needle shaft port in the tip shield body can be formed by slitting a pliable tube. In some configurations, the needle shaft port may be held open by a tab or a post-like feature, such as adjacent to the proximal end of the tip shield. The tab or post-like feature may be used in connection with any of the tip shields described above and may be associated with the housing <b>36</b> or other component of the vascular access system. The use of a tab feature to hold the needle shaft port open may reduce the frictional drag on the needle shaft as it is being withdrawn and may enable the tip shield to more completely seal once the tip is received in the chamber and the tab feature is disengaged from the tip shield allowing the needle shaft port to close.

Additionally or alternatively, the enlarged shaft region of the needle may be non-symmetrical and/or may be formed other than by crimping the shaft or affixing a ferrule. Moreover, the enlarged shaft region can be retained to prevent proximal movement beyond the tip shield proximal end by means other than the restricted width of the slot.

As still further variations on the inventive principles of the present application, the means for activating the tip shield may be varied in any suitable manner. For example, in addition to or as an alternative to the restricted opening of the housing and cooperating inclined slope (see <figref idrefs="DRAWINGS">FIGS. 2-6</figref>), the needle tip can be pressed or introduced into the chamber of the tip shield by pressure from a biasing member encouraging the tip shield towards the needle shaft.

It is believed that the disclosure set forth above encompasses multiple distinct methods and/or apparatus with independent utility. While each of these methods and apparatus has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the disclosures includes all novel and non-obvious combinations and sub-combinations of the various elements, features, functions and/or properties disclosed herein. The principles of the present disclosure may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein, The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the disclosure is, therefore, not limited by the foregoing description or the following claims, and all changes that come within the meaning and range of equivalency of the foregoing description and/or the following claims are to be embraced within its scope. Similarly, where the description and/or the claims recite “a” or “a first” element or the equivalent thereof, such description should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.

It is believed that the following claims are directed to certain combinations and sub-combinations that correspond to disclosed examples and that are believed to be novel and non-obvious. Other combinations and sub-combinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different combination or directed to the same combination, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the present disclosure.